Flexible curtain valve unit



Nov. 12, 1968 J. BURDOCK FLEXIBLE CURTAIN VALVE UNIT Filed April 22, 1966 ATTORNEYS United States Patent 3,410,311 FLEXIBLE CURTAIN VALVE UNIT Joseph L. Burdock, Old Greenwich, Conn., assignor to Universal Oil Products Company, Des Plaines, Ill., a corporation of Delaware Filed Apr. 22, 1966, Ser. No. 544,528 3 Claims. (Cl. 137-62528) ABSTRACT OF THE DISCLOSURE A flexible curtain valve for large gas ducts comprising a fixed upper drive roller, a vertically movable lower idle roller, and a downwardly looped flexible curtain running therebetween. The idle roller divides the curtain into a downstream panel portion and an upstream panel portion. The upper edge of the downstream panel is fixed, the downstream panel contacting and being supported by a lateral grid. The curtain passes under and around the idle roller, the upstream panel portion of the curtain extending from the upstream tangential edge of the idle roller to the downstream tangential edge of the drive roller. This reverse looping arrangement assures continuous urging both of the idle roller and the downstream curtain panel into a tight seal with the grid.

The present invention is directed to a modified flexible roll-curtain construction which provides a tight valvelike seal and is particularly adaptable for use in large ducts to control gas or air flow.

There has been prior use of roller type flexible curtains to provide an adjustable damper means within boiler uptake ducts or in by-pass flue passageways and the like. However, such damper constructions have not been suitably designed or constructed to properly serve as a valving unit and substantially stop gas or air flow under full vacuum conditions or under low superatmospheric pressure of up to the order of 50p.s.i.g.

It may be considered one object of the present invention to provide a flexible curtain valve unit with a downstream open grid type of wall section adapted to be placed transversely across a duct and to utilize a roller arrangement such that the sealing curtain is inherently urged into tight contact with such wall section.

It may also be considered an object of the present invention to utilize an aligned, smooth inner grid surface for the downstream wall section which shall be used in combination with a flexible rubberized curtain surface such that a good pressure tight seal is obtained within the unit.

In one embodiment, the invention provides an adjustable flexible curtain valve unit for large gas ducts, which comprises in combination, spaced apart open wall sections adapted to be placed transversely across a duct and to provide a substantially vertical open slot section for up and down curtain movement therein, an open grid type section extending across the inside face of at least the downstream wall section of the unit and providing a lateral curtain support member, a downwardly looped imperforate flexible curtain passing under a lower movable idle roller maintained in said open slot section to provide transversely a downstream panel portion and an upstream panel portion, with the upper horizontal edge of the downstream panel portion of said flexible curtain attached to a top inner edge portion of the downstream wall section whereby the outer surface of the downstream panel of the curtain will readily seal against the inner face of the grid section of such wall section, a fixed location upper drive-roller extending horizontally across the top of said slot section and having the other upper edge portion of said flexible curtain connecting to said driveroller, the latter being controllably moveable to wind and unwind the upstream panel portion of the curtain from the downstream tangential edge of the drive-roller whereby there is a reverse looping of the curtain over such roller with respect to the curtain looping over the lower idle roller and a resulting urging of the latter and of the downstream curtain panel into a tight seal with the inner grid surface of the downstream wall section.

It is an important feature in effecting the assembly of the present unit, that the flexible curtain be attached to and initially wound around the drive-roller such that the winding and unwinding of the upstream panel portion of the looped curtain be from the downstream tangential edge of such roller. This arrangement then results in the continuous urging of the idle roller, as well as the down stream panel portion of the curtain, to maintain contact with the downstream gridlike wall section.

A preferred embodiment of the unit also incorporates suitable guide means for the lower idle roller to in turn provide good alignment and contact between the downstream face of the curtain and the inner face of the downstream gridlike Wall section. The guide means may, for example, comprise flanged sections at the ends of the idle roller which are adapted to ride vertically within suitably formed slot means extending vertically along each inner edge portion of the downstream wall section. In the case of very large or side ducts, the flexible curtain seal member may be divided in two or more vertical sections and there may be one or more intermediate flangelike projec tion from the roller with opposing slot means formed within the inner face of the downstream wall section so as to assist in maintaining alignment for the idle roller and for insuring good contact between the curtain sections and the inner face of the downstream wall so as to insure a tight seal against air or gas flow through the duct when the curtain is in the lower blocking position.

Reference to the accompanying drawing and the fol lowing description thereof will serve to better clarify the present improved flexible curtain valve construction as well as point out additional advantageous features for maintaining a substantially leakproof type of valving unit.

FIGURE 1 of the drawing is a sectional elevational view through one embodiment of the valving unit, indicating the arrangement of the idle roller and the method of aligning the flexible curtain with respect to the upper drive roller.

FIGURE 2 of the drawing is a partial sectional plan view through one end of the valving unit, as provided by line 2-2 in FIGURE 1, indicating flanged guide means at the end of the idle roller.

FIGURE 3 of the drawing indicates in a partial sectional plan view one means for providing multiple curtain panels and an intermediate guide means between the lower idle roller and the inner face of the downstream wall section of the unit.

Referring now particularly to FIGURES 1 and 2 of the drawing, there is indicated diagrammatically duct means 1 which is adapted to have a curtain type valving unit 2 positioned transversely thereacross. Such unit has an upstream wvall section 3 with flange means attached to connect with the duct means 1 as well as a downstream wall section 4 which also has flange means to connect with the duct 1. The inner face of the downstream wall section 4 is provided with a gridl-ike section 5 such that there is a plurality of cross members to in turn provide a uniform lateral support for the downstream face of a flexible curtain panel 6. The grid portion 5 shall, of course, be primarily open to permit substantially unblocked gas or air flow through the duct under conditions where the curtain is raised and there is in effect no valving of the gas flow through duct 1. On the other hand, the grille or grid 5 shall have a plurality of vertical and horizontally spaced members such that there is adequate support for the curtain panel 6 to preclude its billowing and deforming when effecting a gas seal in the duct 1. Actually, the spacing of the members of the grid in each direction may be constructed in different units to vary with diflerent pressure drops to be encountered. In the instance of a curtain valve operating against substantially fully vacuum conditions, there may be utilized a grid or grille where the spaced lateral members are on approximately 2" centers. In addition, a preferred embodiment of the unit should provide milling or other means for effecting a uniform smooth surface for the entire inside face of this grid portion of the downstream wall section such that the curtain panel can effect .a tight surface contact with the entire grid section and substantially preclude any gas leakage therethrough.

As best shown in FIGURE 1 of the drawing, the flexible curtain has a fixed horizontal edge .along the top of the downstream wall and grid section at zone 7, whereby the downstream panel 6 will directly contact the inner face of grid and then pass under an idle roller 8 to provide an upstream panel section 9 which in turn wnds and unwinds from the downstream tangential edge of the portion 10 of the flexible curtain that is wound around a drive roller 11. The latter extends horizontally across an upper housing section 12 and may be supported from suitable bearing means at each end thereof, which are not shown in the drawing. An axial portion 13 for the drive roller 11 is indicated as extending through one end of the housing section 12 and, further, as having suitable pulley and belt drive means 14 to connect to a. reversible motor 15 at the top of the unit. With the use of a reversible motor 15 connective to the drive roller 11, there is means for readily turning the latter in either the wind or unwind direction. When the drive roller 11 is operated to unwind the flexible curtain 10 therefrom so as to permit the lowering of the idle roller 8 into a bottom position, shown in dashed lines, there will be an entire closing off and sealing of the downstream wall section by the downstream panel portion 6. Conversely, as the motor is operated to wind the curtain at lltl around the roller 11 there will be a lifting of the idle roller 8 to any intermediate position, such as shown in full in the present FIGURE 1 of the drawing, or to an upper elevated position where there is a full opening for gas flow through duct 1.

It will be noted, as previously pointed out, that by having the upstream panel section 9 cross over to the downstream edge of the wound curtain portion 10 there is in effect a reversing roll arrangement which causes panel section 9 to hold the idle roller 8 tightly against the inner face of grid section 5, whereas, on the other hand, if the panel section 9 is merely around roller 11 from the upstream tangential edge, then roller 8 would be hanging loosely between the spaced wall sections 3 and 4 and there would be no tight seal with grid portion 5. Further, a preferred embodiment of the unit also utilizes a rubberized fabric or at least a rubberized facing for the flexible curtain material so that there can he a tight, non-slipping contact along the downstream face of panel section 6 and grid portion 5. It is not, however, intended to limit the present invention to any one type of material, inasmuch as the curtain may comprise cotton or nylon fabrics which are rubberized and non-porous so as to preclude any air flow therethrough. Other non-porous rubber coated materials may well be used as long as they are generally of a rugged non-deforming nature. In some instances, temperature conditions or a particular service may have a bearing on the type of fabric which is to be utilized. The usual asbestos curtain materials, with a rough face and which have been used in certain curtain damper constructions, are, however, entirely unsuitable to serve as the curtain in a pressure tight valve unit of the present type.

As best shown in FIGURE 2 of the drawing, there is indicated a vertical slotted area 16 provided between the vertical side edge of grid portion 5, as defined by member 17, and the inner face of the partitioning member 18 which is shown extending vertically along the inside end wall portion of the unit 2. At the same. time, there is provided an outwardly extending flange portion 19 (which can be at each end of the idle roller 8) whereby there is maintained an accurate vertical rise and fall of the idle roller during such periods as there is the winding and unwinding of flexible curtain 10 from drive-roller 11. The flange members 19 at each end of the roller 8 may also serve to maintain the flexible curtain in substantial vertical alignment with the inner face of the grid portion 5 as the idle roller is lowered or raised along the inner face of the downstream wall section.

In connection with idle roller means accommodating a wide curtain type valve, with two or more separate sections of curtain material within a wide duct means, there may be an intermediate flange, such as 20, on idle roller means 8' and a suitable intermediate vertical slot 21 provided within the downstream wall portion 22 of a multiplesection valving unit. In the present instance, there is indicated two spaced apart channel members 23 to provide the slot 21 which in turn shall extend the full vertical height of the duct section and be able to accommodate the guide flange on the idle roller. Also, in this instance there would be two separated downstream panel portions 6' from separate rolled curtain sections which in turn attach to an upper drive roller not shown. The drive roller and the reverse looping of the flexible curtain between the bottom of the idle roller and the upper drive roller would, of course, be similar to that shown in FIGURE 1 of the drawing, with each curtain section thus operating in a side by side relationship in the same manner as that carried out for a single panel. Extending each way from the channel members 23 and from plate members 24, there would also be inner grille sections 25 in order to provide adequate lateral support for the curtain sections 6' in the same manner as that heretofore described in connection with grid portion 5 for FIGURE 1 of the drawing.

It is not intended to limit the present invention to any one method or means for effecting certain details of construction, such as for attaching the fixed upper edge of the flexible curtain member or for providing the motive power operating the drive-roller which in turn effects the winding and unwinding of the curtain section or sections, inasmuch as there may be various structural and mechanical modifications utilized in connection therewith. It is, however, necessary to maintain the reverse loop arrangement for the flexible curtain and the upper attachment of the fixed edge thereof so that there can be the desired full and complete engagement of the downstream face of the downstream panel section of the curtain against the inner face of the grid section so as to in turn obtain the tight valve-like seal against gas flow. The present embodiment indicates, in FIGURE 1, a cross plate or strap members 26 along the lower edge portion 28 of the valving unit 2 such that there is a bottom stop for the lower positioning of idle roll 8, however, such stop members 26 shall be sufficiently low as to permit a proper sealing between the lower edge portion of panel 6 and the lower edge of grid section 5. There is also indicated a suitable drain outlet 27 from the lower housing section 28 so that any condensate collecting therein may be readily removed from the inside of the unit.

I claim as my invention:

1. An adjustable flexible curtain valving unit for large gas ducts, which comprises in combination, spaced apart open type wall sections adapted to be placed transversely across a duct and to provide a substantially vertical open slot section for up and down curtain movement therein, a vertical open grid type section extending across the inside face of at least the downstream wall section and providing a lateral curtain supportmernber, a downwardly looped imperforate flexible curtain passing under a lower vertically movable idle roller maintained in said open slot section to provide a downstream panel portion and an upstream panel portion for such curtain, with the upper horizontal edge of the downstream panel portion of said flexible curtain attached to a top inner edge portion of the downstream wall section whereby the outer surface of the downstream panel of the curtain will readily seal against the inner face of the grid section of such wall section, said idle roller being provided with flanged guide means projecting therefrom and vertical edge portions of said downstream wall section of said unit being provided with vertical slot means opposing said flanged means on said idle roller whereby the latter can ride vertically upwardly and downwardly to maintain a vertical guide means for the idle roller and for maintaining close alignment of the downstream curtain panel into contact with the inner surface of said grid section, a fixed location upper driverroller extending horizontally across the top of said slot section and having the other upper edge portion of said flexible curtain connecting to said drive-roller, the latter being controllably moveable to wind and unwind the upstream panel portion of the curtain from the downstream tangential edge of the drive-roller whereby there is a reverse looping of the curtain over such roller with respect to the looping over the lower idle roller and a resulting continuous urging of the latter and of the downstream curtain panel into a tight seal with the inner grid surface of the downstream wall section.

2. The curtain valving unit of claim 1 further characterized in that said flexible curtain comprises a non-perforate material having a rubberized type exterior surface adapted to engage the inner face of said grid portion of the downstream wall section and the inner surface of such grid shall be smooth and in accurate alignment, whereby there is a resulting pressure tight seal provided between the curtain and the surface of the grid portion.

3. The curtain valving unit of claim 1 further characterized in that said drive-roller is connected to and operated by a reversible motor means whereby there is a power operation of such drive-roller to effect the winding and unwinding of the flexible curtain over the drive roller and power operation for lifting and lowering of the idle roller and the lower loop of the flexible curtain.

References Cited UNITED STATES PATENTS 1,556,328 10/1925 Hutchins 251 2,349,368 5/1944 Myers 251 2,548,333 4/1951 Anderson 137-62528 X ARNOLD ROSENTHAL, Primary Examiner. 

